In the advanced semiconductor process, the breakdown voltage of the transistor is decreased to 1V, and it is very harmful to receiver's linearity. In addition, because the out-of-band blockers may be higher than 0 dBm while the in-band signal may be −99 dBm in the 3GPP specification, the conventional art generally uses a surface acoustic wave (SAW) filter in a printed circuit board to reject the out-of-band blockers, or enlarges a supply voltage of the receiver and uses the differential structure to tolerate the out-of-band blockers, or uses an external balun to provide differential input signal and extra out-of-band blockers rejections. However, in order to save the manufacturing cost and improve GSM (Global System for Mobile Communications), GPRS (General Packet Radio Service), EDGE (Enhanced Data rates for GSM Evolution) sensitivity, the external SAW filter is suggested to be removed. In addition, as the growing demand of the cellular bands, the input ports of the receiver may be more than twenty, and the input port is necessary to be single-ended. Hence, these conventional arts are not suitable for the present demands of the receivers.